The Syrian regime may be on the verge of an important advance in that country's civil war. Rebels said today that they've agreed to a conditional retreat from parts of the city of Homs. The forces of Syrian President Bashar al-Assad have made a big push there lately.

NPR's Alice Fordham has the latest.

ALICE FORDHAM, BYLINE: Activists in Homs say that under the deal, they would leave the ruined neighborhoods where they have been besieged for almost two years. More than a thousand fighters are set to leave with their weapons and be allowed to head to rebel-held territory north of the city. In exchange, Syrian soldiers and their paramilitary supporters would regain control of almost all the rebellious areas of a city once known as the capital of the revolution.

ABU AL-HARITH: (Foreign language spoken)

FORDHAM: A negotiator on the rebel side, who goes by the name Abu al-Harith, reached by Skype, claims the regime would receive Iranian hostages - military advisors to Assad's forces who've been captured on a succession of battlefields.

Rebel negotiators say the United Nations and Iranian diplomats helped broker the deal. U.N. offices in Syria and the Iranian Embassy in Lebanon did not respond to requests for confirmation. The truce was reported in pro-Assad media, though, without mention of the hostages.

The road to the deal has been extremely bloody. Activist Abu al-Harith says a series of car bombs by the Al Qaida affiliate Jabhat al-Nusra were a key factor in pushing the regime to make the truce. In the last week, about a hundred civilians were killed in pro-government areas of Homs.

AL-HARITH: (Foreign language spoken)

FORDHAM: He says, you've seen the bombings. Those were the replies to the National Defense Forces - a pro Assad militia - who didn't want any truce.

Abu al-Harith hopes the retreat will happen in the next 48 hours. There are no winners or losers, he insists. But if the fighters do leave this bitterly fought-for territory, it would be the latest in a series of victories for Assad.